The present invention generally relates to a device for transferring solid articles and more particularly, to a device for transferring a large amount of solid articles such as pharmaceutical tablets in a short period without causing damage to the solid articles.
Generally, devices for transferring solid articles in production processes include, for example, a rotary screw type transfer device for transferring solid articles by rotating a screw, a pneumatic conveying type transfer device in which solid articles are fed by air blown into a pipe or by suction under vacuum and mechanical transfer devices such as a bucket type transfer device, a belt type transfer device, a shooter type transfer device, etc.
In these mechanical transfer devices, external force applied to solid articles during their transfer may cause damage to surfaces of the solid articles, thereby resulting in fracture or chipping of the solid articles in some cases. Therefore, in such cases, the mechanical transfer devices cannot be used for transferring pharmaceutical tablets or the like.
Especially, transfer of sugar-coated tablets is a final process of production of the tablets. Since the final process should maintain a strict quality level, it is difficult for these mechanical transfer devices to be used for transferring the sugar-coated tablets. Therefore, in many cases, the tablets are put into a transfer container so as to be transferred together with the transfer container during transfer from a sugar coating process to the subsequent printing and inspection process. It is also considered that this transfer is automated by using an unmanned transfer carrier, etc. However, this automation requires complicated apparatuses and thus, cannot be performed at low cost. As a result, transfer from the sugar coating process to the subsequent printing and inspection process is generally performed manually by using a pallet.
A shuttle type transfer device shown in FIG. 1 is known as an automatic transfer device for transferring solid articles A such as tablets without causing damage to the solid articles A. In the known shuttle type transfer device, front, middle and rear transfer plates 51a, 51b and 51c are coupled by a flexible shaft 52 so as to constitute a shuttle 50 and this shuttle 50 is disposed in a pipe 53. An air flow path 58 for transferring the solid articles A is provided at one end 54 of the pipe 53.
The solid articles A loaded from a loading aperture 56 at the end 54 of the pipe 53 are accommodated in a space between the front and middle transfer plates 51a and 51b and are transferred towards the other end 55 of the pipe 53 by pneumatic pressure. After the shuttle 50 has reached the other end 55 of the pipe 53 and the solid articles A have been discharged from a discharge aperture 57, vacuum pressure for sucking air in the pipe 53 from the air flow path 58 or pneumatic pressure from the other end 55 of the pipe 53 returns the empty shuttle 50 to the end 54 of the pipe 53, which has the loading aperture 56.
In this known shuttle type transfer device, since the solid articles A are transferred together with the shuttle 50 reciprocating in the pipe 53, the solid articles A do not impinge upon each other and are seldom subjected to external force. Therefore, in addition to such a merit that the solid articles A can be transferred without causing damage to the solid articles A, the known shuttle type transfer device is also advantageous in that since the solid articles A are transferred in the pipe 53, an in-line system or a closed system can be provided.
However, in the known shuttle type transfer device, the amount of the solid articles A capable of being transferred by one reciprocation of the shuttle 50 is limited by capacity of the shuttle 50 for accommodating the solid articles A. Furthermore, the known shuttle type transfer device has such a drawback that since during return of the shuttle 50 to the loading aperture 56, the shuttle 50 is transferred in an empty state and thus, transfer of the solid articles A is suspended, efficiency for transferring the solid articles A is quite low, so that a large amount of the solid articles A cannot be transferred in a short period.
Meanwhile, since the known shuttle type transfer device requires a power source for supplying or sucking air in order to reciprocate the shuttle 50, maintenance and inspection of the known transfer device are troublesome and the known shuttle type transfer device cannot be obtained at low cost.